A large number of crew will work and live on board for many large special purpose vessels with the continuous exploration of ocean, which will put forward higher and higher requirements for the ship safety. In general, safe return to port is for passenger ships, and there are few engineering ships can meet this requirement. This paper introduces the design method of the electrical system and its influence on the design of the electrical system for a deepwater pipe-laying crane vessel that meets the requirement of safe return to port. It can provide reference for the design of the similar ships in the future.